1. Field of the Invention
This invention relates to microelectronic and microelectromechanical devices comprising carbon nanotube components, and to methods for making same.
2. Description of the Related Art
U.S. Pat. No. 5,872,422 issued Feb. 16, 1999 for xe2x80x9cCarbon Fiber-Based Field Emission Devicesxe2x80x9d discloses cold cathodes for use in electronic devices and displays and methods of making and using cold cathode devices. Cold cathodes are provided comprising a surface havingcatalytically grown carbon-containing fibers as robust electron emission sources. As described in U.S. Pat. No. 5,872,422, field emission cathodes are fabricated by selectively depositing a catalyst film on the desired area of a substrate surface, followed by catalytic growth of the carbon-containing fiber emitter structures. Field emission displays are constructed using the carbon-containing fiber-based cold cathodes. U.S. Pat. No. 5,872,422 also describes precursor substrates suitable forcatalytically growing electron emitter structures, as well as methods of producing other devices, e.g., cold cathode vacuum fluorescent displays, and components for such devices by catalytic growth of carbon-containing fiber structures.
The present invention extends the technology of U.S. Pat. No. 5,872,422 to microelectronic and microelectromechanical structures based on carbon nanotubes.
The present invention in one aspect relates to a microelectronic or microelectromechanical device, comprising a substrate and a fiber formed of a carbon-containing material on the substrate. Such fiber may for example electrically interconnect two or more non-insulative regions on the substrate. Alternatively, the fiber may have a free end that istranslationally mobile in the device. The fiber may be doped, e.g., to constitutepn junctions or other device structure, and the fiber may be bonded by spot welding to provide structural integrity to the interface of the fiber and an associated element or surface to which the fiber is joined. Such dopants may be any suitable species e.g., the dopant impurities may comprise H, B, Al, N, P, Li, Be, Na, or K.
In another aspect, the invention relates to an external stimulus-mediated wiring system comprising carbon microfiber connectors in a microelectronic or microelectromechanical device structure.
A further aspect of the invention relates to a method of forming a carbon-containing fiber on a substrate, comprising growing at least one carbon-containing fibercatalytically on a surface of the substrate by heating the substrate in the presence of a carbon source to a temperature sufficient to grow the fiber on the substrate surface, as a component of a microelectronic or microelectromechanical device.
Another aspect of the invention relates to a method of forming a wiring system comprising carbon microfiber connectors in a microelectronic or microelectromechanical device structure, including the steps of: providing an external stimulus-mediated growth circuit comprising a multiplicity of imaging inputs and input-responsive growth means including a substrate having carbon microfiber growth catalyst thereon, exposing the imaging inputs to stimulation images, responsively generating microfiber growth output signals from the imaging inputs, and generating carbon microfiber growth on the substrate in the presence of a carbon source, at loci of the substrate determined by the generated microfiber growth output signals.
Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.
As used herein, the terms xe2x80x9ccarbon containing microfibersxe2x80x9d and xe2x80x9ccarbon nanotubesxe2x80x9d are used interchangeably. The carbon nanotubes may comprise only a single graphite layer (single-walled nanotubes), or alternatively may include multiple graphite layers (multi-walled nanotubes). A carbon containing microfiber structure may comprise one carbon nanotube or a bundle of many carbon nanotubes. The nanotube may be without defects, or it may contain various degrees of structural defects, impurities or metallic particles atan extremity (tip) or other portions thereof